Man is an animal, but he is more than that. He exhibits an activity that brute animals do not. He can reason, and he can make free choices. Although he has five external senses, internal senses (i.e., imagination, sense memory, etc) as well as two sense appetites from which all the emotions are derived (love, desire, satisfaction, hate, aversion, sorrow; hope, despair, daring, fear, anger), man can reason to conclusions on the basis of judgments composed of concepts (i.e., All dogs are animals, Fido is a dog), and he can make choices that are contrary to his appetites.
For example, he can reason that although certain foods make him feel good, they are not healthy, and so he can choose to sacrifice them, although his appetites still desire them. This is called "will power", or the power of the will.
Let's consider human knowledge again. Man has ideas. If we consider carefully these ideas, we notice that they are very different from images. Consider the idea of health, for example, or the idea of man, or canine, equality, quantity, quality, education, happiness, etc. There is no corresponding image of these. What does equality look like? What color is education? How tall is humanity? Is canine furry? Is quantity heavy or light?
To say that man has ideas is to say that he understands the essences of things, that is, he understands what things are. The essence of a thing answers the question: "What is it?" For example, the essence of man is "human". The essence of all these dogs, that one fundamental quality they all have in common, is canine.
Animals perceive, that is, they sense, but they do not grasp the essences of things. Essences are universal. You and I know not just this tree or that tree, but tree in general. When you study geometry, you do not know this triangle or that triangle, but all triangles, because you come to understand the essence of triangle (triangularity). When we study psychology, we don't wish to know this or that man as such, but man in general.
Let's consider the will. You and I have a will, but willing is not the same as the passion of desire. We have eleven basic emotions. These stem from two appetites: the concupiscible and irascible. The concupiscible appetite is the pleasure appetite, and it desires the pleasant, or things that are pleasing to the senses, like pizza, or chocolate (love, desire, satisfaction). Sometimes a thing is not so pleasant, such as the smell of a skunk. In this case, you experience hate. As it gets closer, you experience the emotion of aversion. If you can't get away from it, you experience sorrow.
A pleasant thing might be difficult to acquire. In this case you experience the aggressive appetite. You begin to hope for it and so you go looking for ways to get it. If the pursuit is hopeless, you experience the emotion of despair.
Suppose you see some sensible thing that you experience as bad or evil, and which is difficult to avoid, like a pit bull. This gives rise to another emotion, namely fear. Perhaps you think you can fight this dog and defeat it. You might then experience daring. Suppose it bites you in the arm. You will likely experience the emotion of anger.
Those are your eleven basic emotions. Human beings, however, can rise above their emotions. You can eat something you hate, you can face something you fear, you can choose not to be moved by your anger, or deterred by your sorrow. How is that possible? You have a will. Hence, man is more than an animal.
Just as there is in us the emotion of love (I love pizza, I love sugar cookies, etc.), there is also the love that is an act of the will. The love that is an act of the will is the highest kind of love. It is the one love that is specifically human. Here, I will what is good for you as if you were another me.
This kind of love follows upon human knowledge. For example, I not only sense you (I see you), but I also know what you are, namely, a human person of the same nature as me (human nature). You are like me essentially.
Now, I want or will the best for myself, quite naturally. I can choose to will the best for you, as if you were another me, because I understand that you are like me essentially.
If I do will the best for you, there is a sense in which I have expanded - not physically, of course, but spiritually. If I will your good, if I will what is best for you, then I love you as if you were another me. I have become you, in a sense. When you are happy, I am happy. When you are sad, I am sad. The more people I love with that kind of love, the larger I become.
There are certain principles or starting points to all knowledge which are self-evident. One knows them in knowing anything. The first principle of speculative reason is called the principle of non-contradiction. The first thing I come to know when I know anything at all is that nothing can both be and not be at the same time and in the same respect. In other words, contradictories cannot be true at one and the same time. If Samantha is in the band, then it is not true that she is not in the band. If you passed the course with an A, then it is not true that you failed. If, for example, a passing mark meant a failing mark, and a failing mark meant a passing mark, communication would be impossible; for knowledge would be impossible.
The logical formulation of the principle of non-contradiction is the following: Nothing can be both true and not true at the same time and in the same respect.
Because the principle of non-contradiction is necessarily true, it follows that from nothing comes nothing. If something could come from nothing, then nothing and something would be the same thing. But this would violate the principle of non-contradiction.
Another principle that you and I know naturally is that every effect has a cause. If you hear knocking in the direction of the door, you know that there is a cause of that sound. Why? Because from nothing comes nothing. The effect (knocking) has a cause (knocker).
Now, you also know that the effect cannot be greater than the cause. This means that a thing cannot give what it does not have. If the effect could be greater than the cause, then something could come from nothing. But that is impossible. Hence, the effect is always less than the cause. A thing can only impart what it has. I cannot write you a cheque for 1 million dollars, because I don't have it.
Now, I also know that I am not the cause of "what is" (reality). I also know that reality appears to me as good, as beautiful, as desirable. I know that it is good to be alive, which is why I run when a pit bull comes after me. I desire the fruit on the tree, I desire to see, I desire to know about all that is around me. I desire relationship with others. I am awestruck by the beauty in nature. I climb mountains in order to behold the landscape, which I see as breathtaking. Reality is good and beautiful.
But I am not the cause of it. And I know that you are of the same nature as myself, and so you are not the cause of it. But I want to know, naturally, what is the cause of it.
I know that the cause is not less than the effect, so I know that the cause must have the properties that belong to the effect, namely, goodness, beauty, meaning, etc. I also experience a certain gratitude for what is, since I see it all as good and beautiful and given to me.
I also know that there cannot be an infinite series of causes. If an effect were preceded by an infinite series of causes, the effect would never be. Think of a train going backwards. The caboose is moving, because it is receiving motion from the train car next to it, which in turn is moving because it is being moved by the train car next to it, and so on and so forth. The train cannot be infinite in length. If that were the case, the caboose would never move. Neither would any car on the series move, since it is preceded by an infinite series of movers.
Can a person walk to school if the school were an infinite number of inches away? No, one would never arrive. In fact, if we think about this, one would be always walking, and one would never even get closer to the school, since it is an infinite number of inches away. You'd always be an infinite distance away from the school.
So too, the caboose that is preceded by an infinite series of movers would never have motion imparted to it.
And so man naturally comes to a very confused knowledge that there is a first cause that is uncaused, a first mover that is unmoved (for if the first cause was moved, it would not be first). This First Cause cannot lack what creation has, since the effect cannot be greater than the cause.
Man naturally desires to know this cause, even to express gratitude to this cause, to seek harmony between himself and this "totally other" source of meaning, goodness, and beauty. The word religion means "to bind" (from the Latin: re-ligare). Man seeks to bind himself to this origin, to his origin, the origin of all things.
This one cause is mysterious to him. He attempts to understand and articulate this mystery. He even offers sacrifice, which is a sign of his attempt to achieve some kind of harmony between himself and this mysterious origin; for sacrifice is a sign of love, because it involves the giving up of something for the sake of the other.
And so man naturally seeks God, the essential One, True, Good, and Beautiful. He seeks rest in the good, the true, and the beautiful, the one. The religions of the world are really man's attempts to articulate this mystery and its implications for his life. And since they are man's attempts to understand and articulate it, we can expect these articulations to be a mixture of truth and error. If this God chooses to reveal Himself, however, perhaps then we can expect that revelation to be free from error. And so the most important point is to try to discover whether or not He has actually revealed Himself to man.